Toward a New Evidence-Based Fitting Paradigm for Over-the-Counter Hearing Aids

Purpose This dual-aim study was intended to develop and validate a new fitting paradigm for over-the-counter (OTC) hearing aids. Aim 1 was undertaken to create a limited set of evidence-based preconfigured gain-frequency responses ("presets") for use in OTC devices. Aim 2 tested the efficacy of the presets relative to best-practice verification and determined the best method(s) for older adults to self-select amplification from the set. Method In Aim 1, audiometry data from 267 older adults with mild-to-moderate sensorineural hearing loss were obtained from the National Health and Nutrition Examination Survey database. Using these data and the National Acoustic Laboratories-Non-Linear 2 (NAL-NL2) prescriptive formula, a set of four presets were created that can fit a large percentage of older Americans with presbycusis. In Aim 2, 37 older adults with hearing loss used five methods to select presets. The selection methods were select-by-audiogram, select-by-self-test, select-by-trying, select-by-questionnaire, and random assignment. Using a crossover design, each participant completed speech recognition testing and sound quality ratings in quiet and noise for all selection methods and a verified NAL-NL2 condition. Results The set of presets can fit 67.9% of older Americans with mild-to-moderate hearing loss (Aim 1). Controlling for hearing thresholds and sound quality ratings, liner mixed-effects models indicated that speech recognition scores for select-by-audiogram, select-by-self-test, and select-by-trying were not statistically different from the NAL-NL2 condition. Statistical analysis indicated that select-by-self-test produced outcomes most consistent with individual outcomes for the NAL-NL2 condition (Aim 2). Conclusion This newly developed fitting paradigm may provide efficacy comparable to best-practice verification and could be used in OTC hearing aids.